News

WHAM comes down south

By Katynna Gill

30 March 2009

No, George Michael is not planning a reunion tour in the southern hemisphere of 1980s iconic band WHAM! Instead, a telescope called WHAM - the Wisconsin H-Alpha Mapper - has just been moved to Chile from the USA, with the help of University of Sydney physicist, Dr Greg Madsen.

Dr Greg Madsen (far left), from the School of Physics at the University of Sydney, with (l-r) Kurt Jaehnig, Dr Matt Haffner and Alex Hill from the University of Wisconsin, with WHAM in its new southern hemisphere location.

WHAM has spent the last eleven years on Kitt Peak in Arizona, USA, creating 3D maps of interstellar plasma in the northern sky, as well as other astronomy mapping projects. Now, having been moved to the southern hemisphere, the telescope will allow astronomers to view and map the southern sky.

"We moved the WHAM telescope to the Cerro Tololo Interamerican Observatory in Chile in March this year. The whole process started in April 2008, when WHAM was removed from the pad on Kitt Peak and packed up in a truck," said Dr Madsen, from the School of Physics at the University of Sydney.

"I spent two weeks in Chile in March 2009 with Dr Matt Haffner, Kurt Jaehnig, Dr Ed Mierkiewicz and Alex Hill from the Department of Astronomy at the University of Wisconsin, installing and commissioning WHAM at its new site. We started with three giant wooden crates and made it into a fully functioning telescope in that time!"

With the telescope being entirely remotely operated, Dr Madsen will be able to point WHAM around the sky and obtain new data from his office at the University of Sydney.

"As part of my PhD at the University of Wisconsin, I helped develop the instrument, so I continued my involvement with WHAM in moving it south," said Dr Madsen.

"As we start operating it in the southern hemisphere, other University of Sydney staff will be a part of our science team. Professor Bryan Gaensler and his students here in the School of Physics, in particular, have expressed a strong interest in being involved."

WHAM is designed to study the faint layer of ionised gas, called the Warm Ionised Medium, that pervades our Milky Way galaxy. The Warm Ionised Medium is many thousands of light years thick and much of the energy in it appears to come from active star formation.

The Wisconsin H-Alpha Mapper telescope - WHAM - in its new southern hemisphere location at the Cerro Tololo Interamerican Observatory in Chile.

"The Warm Ionised Medium is diffuse - it's made of very low density gas - so it's difficult to see with traditional astronomical instruments. Instead of taking images of this gas, WHAM is able to detect the Warm Ionised Medium by measuring spectra of very faint H-alpha emission from the gas," explained Dr Madsen.

"Using these spectra, WHAM has produced the first ever map of the distribution and motion of diffuse ionised gas in our Galaxy," said Dr Madsen.

"Now with WHAM in the southern hemisphere, we're hoping to find more data that will help us answer big questions about how galaxies work, such as: Where does the energy produced in the star-forming regions of our Galaxy go? How does that energy propagate away from these birth sites? How does this energy change as it travels, and how is it deposited back into our Galaxy?"